The subject matter disclosed herein relates generally to a system and method for cooling a dynamoelectric machine. More specifically, the subject matter disclosed herein relates to a system and method for controlling the flow of a cooling medium to improve dynamoelectric machine efficiency.
There are many sources of loss in dynamoelectric machines that can adversely affect machine efficiency, for example, windage loss. Windage loss may be described as power absorbed by the air surrounding the rotor as a result of the relative motion between the stator and the rotor. The power absorbed is supplied by some type of motor or turbine, and this lost or wasted power is not converted into useful energy. It can be seen that windage loss decreases the overall efficiency of the dynamoelectric machine. Another undesirable characteristic of windage loss is that power absorbed is converted into heat which increases the temperature of the stator and/or rotor. The resistance of a conductor (for example, rotor coils or stator coils) increases as the temperature of the conductor increases. As the conductor resistance increases, the overall dynamoelectric machine efficiency decreases.